Cooling fan without returning flow

ABSTRACT

A cooling fan without returning flow comprises a motor stator, a frame and a motor rotor. The frame is joined to the stator with a support device at the inlet side thereof. The motor rotor is disposed at the stator. A fan blade set is disposed under the rotor and at the outlet side of the frame. An airflow area of the outlet can be increased to prevent the outlet side from producing a stagnation zone so as to increase cooling area and reduce noise.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related to a cooing fan without returning flow and particularly to a cooling fan, with which the area of airflow at the outlet can be increased largely and no stagnation zone produced under the fan blades such that the cooling area can be increased and noise can be reduced.

2. Brief Description of the Related Art

Due to electronic components being developed rapidly and the time pulse of running increasing, heat generated from the electronic components increases too. Thus, how to dissipate a deal of heat is an important subject dealing with designing the electronic components in order to operate the electronic components smoothly.

Referring to FIGS. 1 to 4, the conventional cooling fan 1 includes a motor stator 11 and a motor rotor 12. The stator 11 has a baring sleeve 111 and the bearing sleeve 111 is surrounded with a coil 112. The hub 121 of the rotor 12 is attached with a fan blade set 122. The hub 121 has a shaft 121 a and a magnet 123 is placed inside the hub 121. After the rotor 12 being mounted to the stator 11, the motor 12 can rotate by way of the coil 112 and the magnet 123 acting with each other. Referring to FIG. 5, when the cooling fan runs, the airflow generated from the fan blade set 122 can form a airflow stagnation zone under the hub 121 and it results in the airflow being unable to move smoothly. Thus, the overall effect of heat dissipation of the cooling fan is influenced significantly.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a cooling fan without returning flow with which airflow area at the outlet side thereof can be increased effectively.

Another object of the present invention is to provide a cooling fan without retuning flow with which no airflow stagnation zone can occur under the fan blade set thereof.

A further object of the present invention is to provide a cooling fan without retuning flow with which low noise can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

The detail structure, the applied principle, the function and the effectiveness of the present invention can be more fully understood with reference to the following description and accompanying drawings, in which:

FIG. 1 is an exploded perspective view of conventional cooling fan;

FIG. 2 is another exploded perspective view of the conventional cooling fan;

FIG. 3 is an assembled perspective view of the conventional cooling fan;

FIG. 4 is another assembled perspective view of the conventional cooling fan;

FIG. 5 is a sectional view of the conventional cooling fan;

FIG. 6 is an exploded perspective view of the first embodiment of a cooling fan according to the present invention;

FIG. 7 is another exploded perspective view of the first embodiment of a cooling fan according to the present invention;

FIG. 8 is an assembled perspective view of the first embodiment of a cooling fan according to the present invention;

FIG. 9 is another assembled perspective view of the first embodiment of a cooling fan according to the present invention;

FIG. 10 is a sectional view of the first embodiment of a cooling fan according to the present invention;

FIG. 11 is an exploded perspective view illustrating another type of central part of the first embodiment according to the present invention;

FIG. 12 is an assembled perspective view of FIG. 11;

FIG. 13 is a sectional view of FIG. 11;

FIG. 14 is an exploded perspective view illustrating a further type of central part of the first embodiment according to the present invention;

FIG. 15 is an assembled perspective view of FIG. 14;

FIG. 16 is a sectional view of FIG. 14;

FIG. 17 is a perspective view illustrating another type of the fan blades being mounted to the rotor of the motor in the first embodiment of the present invention;

FIG. 18 is an exploded perspective view illustrating the fan blades being before mounting with the rotor of the motor shown in FIG. 17;

FIG. 19 is a perspective view illustrating a further type of the fan blades being mounted to the rotor of the motor in the first embodiment of the present invention;

FIG. 20 is an exploded perspective view illustrating the fan blades being before mounting with the rotor of the motor shown in FIG. 19;

FIG. 21 is a perspective view illustrating a further type of the fan blades being mounted to the rotor of the motor in the first embodiment of the present invention;

FIG. 22 is an exploded perspective view of the second embodiment of a cooling fan according to the present invention;

FIG. 23 is another exploded perspective view of the second embodiment of a cooling fan according to the present invention;

FIG. 24 is an assembled perspective view of the second embodiment of a cooling fan according to the present invention;

FIG. 25 is another assembled perspective view of the second embodiment of a cooling fan according to the present invention;

FIG. 26 is an exploded perspective view of the third embodiment of a cooling fan according to the present invention;

FIG. 27 is another exploded perspective view of the third embodiment of a cooling fan according to the present invention;

FIG. 28 is a sectional view of the third embodiment of a cooling fan according to the present invention;

FIG. 29 is an exploded perspective view illustrating the motor rotor and fan blades of the fourth embodiment according to the present invention;

FIG. 30 is a sectional view of the fourth embodiment of a cooling fan according to the present invention;

FIG. 31 is a graph illustrating performance curves of the present invention and the prior art; and

FIG. 32 is a graph illustrating noise and thermal resistance of the present invention and the prior art

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 6 to 9, the first embodiment of the present invention and it can be seen that the cooling fan 2 comprises a motor stator 21, a frame 22, a motor rotor 23 and a fan blade set 24. The stator 21 provides a bearing hub 211 with a coil 212 and is attached at the side of an air inlet 221 by way of support device 222. The rotor 23 has a receiving part to attach with a magnet 232 and the fan blade set 24 is attached to a central part 241. The central part 241 has a shape of stem and an end of the central part 241 has a joining part 25, which can be a shaft.

The joining part 25 is axially connected to the receiving part 23 of the rotor so as to allow the fan blade set 24 being attached to the rotor 23. The rotor 23 with the fan blade set 24 is joined to the bearing hub 211 of the stator 21 such that the rotor 23 can be disposed in a space formed with the support device 222 of frame 22 and the fan blade set 24 is disposed at the side of the outlet 223 of the cooling fan 2.

Referring to FIG. 10, when the cooling fan 2 is powered on, a complete and smooth air flow area can constitute under the fan blade set 24 to increase the air flow area at the side of the outlet 223 due to the rotor 23 being lifted and mounted in the space and the rotor 23 having the central part 241 joining the fan blade set 24 instead of the hub part done in the conventional fan. Hence, the deficiency of a stagnation zone under the fan blade set 24 caused by the hub in the conventional fan can be avoided and noise of the cooing fan can be attenuated such that increasing cooling area and lowering noise can be enhanced effectively.

Referring to FIGS. 11 to 13, the central part 341 of the fan blade set 24 can be made with a conical shape and the tip 341 a of the central part 341 can be disposed at the side of outlet 223 to facilitate air flowing and enhance the effect of heat dissipation. Referring to FIGS. 14 to 16, the central part 341 can be made with a shape of trapezoidal cone and the flat end 341 b of the central part 341 can be disposed at the side of the outlet 22.

Referring to FIGS. 17 and 18, the fan blade set 24 is joined to the central part 241, 341 and is integrally made with the rotor 23 and the joining part 25 so that the fan blade set 24 can be disposed under the rotor 23. Alternatively, the fan blade set 24 is integrally made with the rotor 23 and the joining part 25 directly and is disposed under the rotor 23 instead of being joined to the central part 241, 341. Then, the magnet 23 is attached to the rotor 23 as shown in FIG. 18. Further, referring to FIGS. 19 and 20, the fan blade set 24 is joined to the central part 241, 341 and can be integrally made under an annular member 233. The joining part 25 and the magnet 232 are attached to the rotor 23 and then the annular member 233 is attached to the rotor 23. In addition, referring to FIG. 20, the fan blade set 24 can be made integrally with annular member 233 without being joined to the central part 241, 341. Moreover, referring to FIG. 21, a suitable hook piece 45 can be made on the joining part 325 of the central part 241 341 based on actual need to allow the fan blade set 24 is hooked to the receiving part 231 of the rotor 23.

Referring to FIGS. 22 to 25, the second embodiment of the present invention is illustrated. The bearing sleeve 511 in the stator 51 of the cooling fan 5 is attached with a coil 512 and the frame 52 at the side of inlet 521 is provided with a support device 522. The rotor 53 has a receiving part 531 and is attached with a magnet 532. The fan blade set 54 is attached to a central part 541 and the central part 541 is configured as a stem and a joining part 55 is formed at the central part 541 and the joining part 55 is a shaft. Part of the fan blade set 54 extends to the outer annular plane 533 of the rotor 53. The stator 51 is disposed at the support device 522 of the frame 52 and the joining part 55 of the fan blade set 54 is attached to the receiving part 531 of the rotor 53 such that the fan blade set 54 can be attached to the rotor 53. The fan blade set 54 with the rotor 53 is attached to the bearing sleeve 511 of the stator 51 and the fan blade set 54 is disposed at the side of the outlet 523 of the cooling fan 5.

When the cooling fan 5 is powered on, more powerful airflow can form under the fan blade set 54 due to area of the fan blade set 54 being increased with the fan blade set 54 being disposed under the rotor 53 and part of the fan blade set 54 extending to the outer annular plane 533 of the rotor 53. The airflow at the outlet 523 of cooling fan 5 can be increased to avoid the disadvantage of producing stagnation zone under the fan blade set 54 resulting from hub of the conventional fan such that less noise can occur from the fan. Hence, increasing cooling area and low noise can be obtained effectively.

Referring to FIGS. 25 to 28, the third embodiment of the present invention is illustrated. The stator 61 of the cooling fan 6 attached with a coil 612 reduces upward and is attached to the support device 622 at the inlet side 621 of the frame 62. The fan blade set 64 is fixedly attached under the rotor 63 provided with the magnet 632 and the rotor 63 is fitted to the stator 61. Hence, the airflow area at the outlet side 623 of the cooling fan 6 can be increased without changing structure of the frame 6. Further, another advantage is that the frame 62 has smaller size.

Referring to FIGS. 29 and 30, the fourth embodiment of the present invention is illustrated. The outer annular plane 731 of the rotor 73 is mounted with a plurality of auxiliary fan blades 732 and the fan blade set 74 is axially attached under the rotor 73 such that the airflow at the outlet side 732 of the cooling fan 7 can be increased to promote airflow characteristics and enhance effect of heat dissipation for the cooling fan 7.

It is noted that when the fan blade set (54, 64, 74) in the first to fourth embodiments is attached to the central part (241, 341), the central part (241, 341) can be configured as the shape in the first embodiment and the way of the fan blades (54, 64, 74) joined to the rotor (53, 63, 73) can be the same as that used in the first embodiment to be suitable for actual need during designing and producing.

Referring to FIGS. 31 and 32, curves 81, 82 shown in FIG. 31 are performance curves of the present invention and curve 83 is performance curve of the conventional fan shown in FIG. 31. The curve 82 is performance curve of the fourth embodiment. Curves 84, 85 shown in FIG. 32 illustrate noise in relation with thermal resistance of the present invention and curve 86 illustrates noise in relation with thermal resistance of the conventional fan. It is noted that curve 85 in FIG. 32 is a relation curve of the fourth embodiment. It can be understood that from the two figures, the present invention has smaller thermal resistance than the conventional fan under the same noise in case of the present invention providing lower performance characteristics. Especially, the set-up way of the fourth embodiment has a preferable performance curve and can obtain higher output efficiency of airflow. Therefore, the present invention can provide much better effect of heat dissipation than the conventional cooling fan.

While the invention has been described with referencing to preferred embodiments thereof, it is to be understood that modifications or variations may be easily made without departing from the spirit of this invention, which is defined by the appended claims. 

1. A cooling fan without returning flow, comprising: a motor stator; a frame with an inlet side and outlet side, the inlet side joining the stator with a support device; and a motor rotor, being disposed at the stator; characterized in that a fan blade set is disposed under the rotor and at the outlet side; whereby, an airflow area of the outlet can be increased to prevent the outlet side from producing a stagnation zone so as to increase cooling area and reduce noise.
 2. The cooling fan without returning flow as defined in claim 1, wherein the fan blade set is integrally made with the rotor and is disposed under the rotor.
 3. The cooling fan without returning flow as defined in claim 1, wherein the fan blade set is attached to a central part.
 4. The cooling fan without returning flow as defined in claim 3, wherein the central part is provided with a shape of stem.
 5. The cooling fan without returning flow as defined in claim 3, wherein the central part has a cross section of cone and the tip thereof is disposed at the outlet side of cooling fan.
 6. The cooling fan without returning flow as defined in claim 3, wherein the central part has a cross section of trapezoidal cone with a flat end thereof being disposed at the outlet side.
 7. The cooling fan without returning flow as defined in claim 3, wherein the central part is attached with a joining part to allow the fan blade set being fixedly joined to the rotor.
 8. The cooling fan without returning flow as defined in claim 7, wherein the joining part is a shaft.
 9. The cooling fan without returning flow as defined in claim 7, wherein the joining part is a joining hook piece.
 10. A cooling fan without returning flow as defined in claim 1, comprising: a motor stator; a frame with an inlet side and outlet side, the inlet side joining the stator with a support device; and a motor rotor, being disposed at the stator and providing an outer annular plane; characterized in that a fan blade set is disposed under the rotor and at the outlet side with part of the fan blade set extending to the outer annular plane; whereby, an airflow performance can be enhanced and an area of the outlet can be increased to prevent the lower part of the fan blade set from producing a stagnation zone so as to increase cooling area and reduce noise.
 11. The cooling fan without returning flow as defined in claim 10, wherein the fan blade set is integrally made with the rotor and is disposed under the rotor.
 12. The cooling fan without returning flow as defined in claim 10, wherein the fan blade set is attached to a central part.
 13. The cooling fan without returning flow as defined in claim 12, wherein the central part is provided with a shape of stem.
 14. The cooling fan without returning flow as defined in claim 12, wherein the central part has a cross section of cone and the tip thereof is disposed at the outlet side of cooling fan.
 15. The cooling fan without returning flow as defined in claim 12, wherein the central part has a cross section of trapezoidal cone with a flat end thereof being disposed at the outlet side.
 16. The cooling fan without returning flow as defined in claim 12, wherein the central part is attached with a joining part to allow the fan blade set being fixedly joined to the rotor.
 17. The cooling fan without returning flow as defined in claim 16, wherein the joining part is a shaft.
 18. The cooling fan without returning flow as defined in claim 16, wherein the joining part is a joining hook piece. 19 A cooling fan without returning flow as defined in claim 1, comprising: a motor stator; a frame with an inlet side and outlet side, the inlet side joining the stator with a support device; and a motor rotor, being disposed at the stator and providing an outer annular plane; characterized in that a plurality of auxiliary fan blades are mounted at the outer annular plane, a fan blade set is disposed under the rotor and at the outlet side; whereby, an airflow performance can be enhanced and an area of the outlet can be increased to prevent the lower part of the fan blade set from producing a stagnation zone so as to increase cooling area and reduce noise.
 20. The cooling fan without returning flow as defined in claim 19, wherein the fan blade set is integrally made with the rotor and is disposed under the rotor.
 21. The cooling fan without returning flow as defined in claim 19, wherein the fan blade set is attached to a central part.
 22. The cooling fan without returning flow as defined in claim 19, wherein the central part is provided with a shape of stem.
 23. The cooling fan without returning flow as defined in claim 19, wherein the central part has a cross section of cone and the tip thereof is disposed at the outlet side of cooling fan.
 24. The cooling fan without returning flow as defined in claim 19, wherein the central part has a cross section of trapezoidal cone with a flat end thereof being disposed at the outlet side.
 25. The cooling fan without returning flow as defined in claim 19, wherein the central part is attached with a joining part to allow the fan blade set being fixedly joined to the rotor.
 26. The cooling fan without returning flow as defined in claim 19, wherein the joining part is a shaft.
 27. The cooling fan without returning flow as defined in claim 19, wherein the joining part is a joining hook piece. 